Using a MySQL event to "deactivate" accounts - mysql

Question

I setup a database and one of the columns in a table is "status" (active,inactive,locked). I want the event to compare NOW() to the value of column "pdate" (which is a timestamp), and if greater than 30 days, update the value of "status" to "inactive".
I wrote the following, but I get a few syntax errors :s
CREATE EVENT `expireAccounts_oldPwd` ON SCHEDULE EVERY DAY
DO
USE databasename;
SELECT pdate FROM tablename WHERE status = "active";
FOR EACH ( ROW IN tablename WHERE( ( SELECT DATEDIFF(NOW(),pdate) AS age ) > 30 ) ) {
UPDATE tablename SET status = "inactive";
};
ERROR 1064 (42000): You have an error in your SQL syntax near 'USE databasename' at line 2
ERROR 1064 (42000): You have an error in your SQL syntax near 'FOR EACH ROW IN "tablename" WHERE( ( SELECT DATEDIFF(NOW(),"pdate") AS age )' at line 4
ERROR 1064 (42000): You have an error in your SQL syntax near '}' at line 6
of course 'databasename' was replaced the actual database's name and 'tablename' the actual table's name.
Now at least it's doing something:
+---------------------+
| pdate |
+---------------------+
| 2011-08-11 18:01:02 |
| 2011-08-11 18:03:31 |
+---------------------+
2 rows in set (0.00 sec)
If I don't included USE databasename; on line 2, I get no output.
FINAL CODE:
USE databasename;
DELIMITER %
CREATE EVENT eventname
ON SCHEDULE EVERY 1 DAY
DO UPDATE tablename SET status = "inactive" WHERE status = "inactive" AND DATEDIFF(NOW(), columnname) > 30);
%
I didn't realize events were database-specific (so you have to be in the database when you create it).
Thanks all!

Answer 1

Two event specific things apart from the obvious syntax problems:
Where does your event end? You need to enclose it in a BEGIN/END block (the same way as a stored procedure).
You need to switch the DELIMITER when defining an event (the same way as when you define a stored procedure).
There are two relevant examples at the end of http://dev.mysql.com/doc/refman/5.1/en/create-event.html.
Update:
Also check http://dev.mysql.com/doc/refman/5.1/en/stored-routines-syntax.html for SQL statements which are permitted in stored procedures and events. USE is not permitted.
One more update:
It would be advisable to first try to get your SQL working without putting it in a event. After you have fixed your statements so that they work, try creating a stored procedure out of it. When you get the stored procedure working, you can replace it with an event. This way it will be much easier to sort out the rest of the problems (such as where is the output of the first SELECT supposed to go? etc.).

Answer 2

Is there a reason you can't use a query like this one?
UPDATE tablename SET status = "inactive" WHERE status = "active" AND DATEDIFF(NOW(),pdate) > 30;
I've never even seen FOR EACH in MySQL...

Answer 3

First step's going to be using valid SQL.
SELECT "pdate" FROM databasename.tablename WHERE "status" = "active";
will always cause an error, because column names shouldn't be in quotes. If you enclose a table name in anything, it'd be backticks (`).
SELECT pdate FROM databasename.tablename WHERE status="active";
You have the same problem in the rest of your query.